Adjustable disc spring systems and methods

ABSTRACT

An adjustable disc spring system includes at least one beveled disc spring axially aligned with the adjustable spacer. The adjustable spacer is compressible in a substantially axial direction relative to the at least one beveled disc spring.

TECHNICAL FIELD

This invention relates, in general to disc springs and more specificallyto adjustable disc spring systems and methods for utilizing suchsystems.

BACKGROUND ART

Disc springs, sometimes referred to as Belleville washers, are conicalshaped washers which are designed to receive force in an axialdirection. These springs produce small deflections under high loads, ascompared to other types of springs. Further, it may be desirable toutilize disc springs in restricted spaces due to their high resilience.However, it is also sometimes desirable to adjust components relative toone another in such restricted spaces, including disc springs used incombination with such components. For example, adjustability may bedesirable in a small axial space when adjusting a disc spring relativeto a rolling element ball or a tapered roller bearing in order toaccommodate axial dimensional variations or tolerances due tomanufacturing variations in making the component parts.

Thus, there is a need for an adjustable disc spring systems and methodsfor adjusting disc spring systems.

SUMMARY OF THE INVENTION

The present invention provides, in a first aspect, an adjustable discspring system which includes at least one beveled disc spring axiallyaligned with an adjustable spacer. The adjustable spacer is generallyring shaped and compressible in a substantially axial direction relativeto the at least one beveled disc spring. The beveled disc spring is alsogenerally ring shaped. The axial disc spring system may be mountedaround a shaft or within a cylindrically shaped cavity. The system maybe used where a combination of resilience and adjustability arepreferred.

The present invention provides, in a second aspect, an adjustable discspring system which includes a plurality of beveled disc springs axiallyaligned with an adjustable spacer. The adjustable spacer is compressiblein a substantially axial direction relative to the plurality of beveleddisc springs.

The present invention provides, in a third aspect, a method foradjusting a disc spring system. The method includes axially aligning atleast one beveled disc spring with an adjustable spacer and compressingthe adjustable spacer in a substantial axial direction relative to theat least one beveled disc spring.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention will be readily understood from thefollowing detailed description of preferred embodiments taken inconjunction with the accompanying drawings in which:

FIG. 1 is a side cross sectional view of an adjustable disc springsystem, including two disc springs received by an adjustable spacer, inaccordance with the present invention, said discs being concentricallyexterior to the adjustable spacer;

FIG. 2 is a side cross sectional view of another embodiment of anadjustable disc spring system, including two disc springs configuredwith offsets being received by an adjustable spacer, in accordance withthe present invention;

FIG. 3 is yet another embodiment of an adjustable disc spring system,including offsets of two disc springs being received by an adjustablespacer and the disc springs including axially protruding portions, inaccordance with the present invention;

FIG. 4 is yet another embodiment of an adjustable disc spring system,wherein the disc springs are similar to those shown in FIG. 3 exceptthat the disc springs are concentrically interior to the adjustablespacer.

FIG. 5 is a perspective view of the disc spring system of FIG. 3;

FIG. 6 is a perspective cross-sectional view of the disc spring systemof FIG. 5 taken along lines 6—6;

FIG. 7 is a side cross-sectional view of another embodiment of anadjustable disc spring system, two disc springs configured with offsetsbeing received by an adjustable spacer and the adjustable spacer beingof a multi-convolute form, in accordance with the present invention;

FIG. 8 is a side cross-sectional view of another embodiment of the discspring system as in FIG. 7 except that the two disc springs areconcentrically interior to the multi-convolute form adjustable spacer.

FIG. 9 is a force-deflection graph relating to the disc spring system ofFIG. 1;

FIG. 10 is a force-deflection graph relating to the disc spring systemsof FIGS. 2 and 3;

FIG. 11 is a force-deflection graph relating to the disc spring systemsof FIG. 7;

FIG. 12 is a side cross-sectional view of another embodiment of anadjustable spring system having straight radial portions in combinationwith a tapered roller bearing;

FIG. 13 is an embodiment of two adjustable disc spring systems connectedby a connecting member, in accordance with the present invention;

FIG. 14 is an embodiment of two adjustable disc spring systems connectedby a connecting washer, in accordance with the present invention;

FIG. 15 is another embodiment of an adjustable disc spring system,including two disc springs having deflection limiting stops, saidsprings being received by an adjustable spacer, in accordance with thepresent invention;

FIG. 16 is an embodiment of two adjustable disc spring systems connectedby an adjustable spacer, in accordance with the present invention; and

FIG. 17 is an embodiment of two adjustable disc spring systems connectedby a disc spring of a first disc spring system engaging a ledge of adisc spring of a second disc spring system, in accordance with thepresent invention.

DETAILED DESCRIPTION

In accordance with the principles of the present invention, anadjustable disc spring system having at least one beveled disc springaxially aligned with an adjustable spacer is provided. The adjustablespacer is compressible in a substantially axial direction relative tothe at least one beveled disc spring.

In an exemplary embodiment depicted in FIG. 1, a disc spring system 10includes an adjustable spacer 20, a first beveled disc spring 30 and asecond beveled disc spring 40. The disc spring system is shaped in aform of a ring or cylinder which can be mounted within a cylindricallyshaped cavity or about a shaft.

Adjustable spacer 20 includes a first entrapping flange 50 for receivingfirst disc spring 30 and a second entrapping flange 60 for receivingsecond disc spring 40. First disc spring 30 and second disc spring 40are substantially circular having openings at their centers to receiveadjustable spacer 20. First entrapping flange 50 and second entrappingflange 60 are curved such that their concave interiors abut first discspring 30 and second disc spring 40. Specifically, first entrappingflange 50 abuts first disc spring 30 on a first proximal end 35, a firstbottom side 38, and a first top side 37. Second entrapping flange 60abuts a second proximal end 45, a second top side 47, and a secondbottom side 48 of second disc 40. Further, first disc spring 30 andsecond disc spring 40 are received in first entrapping flange 50 andsecond entrapping flange 60, respectively, such that they are axiallyaligned with adjustable spacer 20.

Also, adjustable spacer 20 includes a compressible portion 70 which islocated axially between entrapping flange 50 and entrapping flange 60while being curved opposite thereto. Compressible portion 70 is adaptedto be compressed in a substantially axial direction relative to firstdisc spring 30 and second disc spring 40, as indicated by an arrow 80.Adjustable spacer 20 is formed to be circular to conform to a firstproximal end 35 and a second proximal end 45 of first disc spring 30 andsecond disc spring 40, respectively. Adjustable spacers of the typeusable in the present invention are disclosed in U.S. Pat. No. 4,067,585to Rode, which is incorporated by reference herein, and made a part ofthis disclosure. However, other adjustable spacers which are capable ofaccepting an axial load and are compressible in the axial directionunder a certain load will suffice.

First disc spring 30 and second disc spring 40 may be conical shapedwashers adapted to receive a stress in the axial direction of arrow 80to act as compression springs, as will be understood by those skilled inthe art. For example, first disc spring 30 and second disc spring 40 maybe Belleville washers, as is known by those skilled in the art.

Disc spring system 10 may be received in a restricted space, forexample, a cylinder (not shown) or another axial space. A first distalend 39 of first disc spring 30 and a second distal end 49 of second discspring 40 may be adapted to contact an inner surface of such a cylinder.For example, first distal end 39 and second distal end 49 may be adaptedto engage the inner surface to inhibit or prevent movement of firstdistal end 39 and second distal end 49 in an axial direction relative tothe cylinder.

In another embodiment of the present invention, illustrated in FIG. 2, adisc spring system 100 includes a first disc spring 130 and a seconddisc spring 140 received in entrapping flanges 150 and 160,respectively, of an adjustable spacer 120. First disc spring 130 andsecond disc spring 140 include a first offset 132 and a second axialoffset 142, respectively. The offsets are located on the inner radius ofthe disc springs. First offset 132 allows adjustable spacer 120 toengage first disc spring 130 interior to an outer axial portion 133thereof By utilizing an offset, an outer surface of a portion used forattachment (i.e. offset 132) may be located interior to entrappingflange 150 without limiting an elastic portion of first disc spring 130.Specifically, a shape of first disc spring 130 is displaced from beingsubstantially straight by offset 132, but its thickness remainssubstantially uniform. Thus, the elastic portion of first disc spring130 is not substantially different from a substantially straightversion. Offset 142 has similar advantages. Offsets may be formed indisc springs through programming of CNC lathe machinery to cut discsprings from solid bars of high strength steel materials. Alternatively,offset shaped disc springs may be stamped, as will be evident to thoseskilled the art.

In another example, depicted in FIGS. 3, 5 and 6, a disc spring system200 includes an adjustable spacer 220 which receives a first disc spring230 and a second disc spring 240. First disc spring 230 further includesan outwardly (i.e. axially) projecting tip 236 which causes an increasein a total deflection range possible for first disc spring 230. Seconddisc spring 240 also includes a projecting tip 246 which projectsaxially but in the opposite direction of the projecting tip of the firstdisc spring. Such projecting tips allow a maximum spring energy of thedisc springs to be utilized because the discs may be first compressedflat and then continued to be compressed elastically to a reverse coneshape from an original free state form. A perspective view of discspring system 200 is depicted in FIG. 5 which makes evident a ringshaped form of disc spring system 200. A cross-sectional view of discspring system 200 taken along lines 6—6 of FIG. 5 is depicted in FIG. 6.In another example (not shown), outer surfaces of projecting tips ofdisc springs may be offset from flat instead of being conically shapeddisc springs as depicted in FIGS. 3–6.

In yet another example, depicted in FIG. 4, a disc spring system 250includes an adjustable spacer 255 which receives a first disc spring 260and a second disc spring 265 at outer radial edges of the disc springs.Thus, the disc springs are positioned concentrically within the innerdiameter of the adjustable spacer. Specifically, adjustable spacer 255receives disc spring 260 at an offset 262 of first disc spring 260 andadjustable spacer 255 receives second disc spring 265 at a second offset266. First disc spring 260 may also include an axially projecting tip280 and second disc spring 265 may include a second projecting tip 282which projects axially but in the opposite direction of the projectingtip of the first disc spring. As noted above, the projecting tips allowa maximum spring energy of the disc springs to be utilized. Further, thereceiving of the disc springs by adjustable spacer 255 at the outerradial edges thereof allow projecting tips 280 and 282 to engage a shaftor other surface at their inner radial ends.

Adjustable spacer 20 (FIG. 1), adjustable spacer 120 (FIG. 2),adjustable spacer 220 (FIG. 3), and adjustable spacer 255 (FIG. 4) areformed of a simple convolute (e.g., a twist or coil) form, asillustrated in FIGS. 1–6. Compressible portion 70, a compressibleportion 170 (FIG. 2), a compressible portion 270 (FIG. 3) and acompressible portion 285 (FIG. 4) may be fabricated of a ductile andwork hardenable alloy such as 304 stainless-steel or Inconel 625, as isknown by those skilled in the art.

An adjustable spacer 320 of a disc spring system 300 has amulti-convolute form, as depicted in FIG. 7. The multi-convolute natureof this spacer allows it to behave in a more predictable manner duringcompression, as compared to the simple convolute form described above.Further, a force-deflection curve of the multi-convolute form isflattened as compared to the simple convolute form, as will be evidentfrom FIGS. 9–11. Specifically, FIG. 9 depicts a force-deflection curvefor disc spring system 10 (FIG. 1) while FIG. 10 depicts aforce-deflection curve for disc spring system 100 (FIG. 2) and discspring system 200 (FIGS. 3–6). FIG. 11 depicts a force-deflection curvefor disc spring system 300 wherein a constant rate of deflection at aconstant force (i.e. 1200 pounds) is evident. Therefore, deflectioncurves depict the response of the system to an axial force applied to,for example, a flat plate placed perpendicular to the central axis. Ineach of the force-deflection curves, at relatively low forces the discspring accounts for a relatively high deflection. At increased forces,e.g., 200 lbs. and higher in FIG. 9, much less deflection occurs due tocompression of the adjustable spacer. Once the spacer has been fullycompressed, e.g., 1,200 lbs., in FIG. 9, additional forces may result inhigher rates of deflection due to the adjustable spacer. After themaximum deflection of the combination is reached, reduction of the forcereduces the deflection. However, since the spacer is adjustable, when noforce is applied the deflection is not zero due to the prior compressingof the adjustable spacer. By varying the shape and configuration of thedisc spring, the higher rates of deflection within the force-deflectioncurves can be varied. Also, by varying the configuration of theadjustable spacer, the low rates of deflection and compressibility ofthe combination can be varied.

This may be particularly important when utilizing an adjustable spacer420 of a disc spring system 400 to adjust a set of rolling element ballor tapered roller bearings 500, for example, as depicted in FIG. 12.Particularly, it is desirable to adjust tapered roller bearings in fineincrements to achieve a precise adjustment. Thus, it is desirable toutilize a spacer which deflects at a constant rate at a particularforce, because this predictability aids in the fine adjustment.Referring to FIG. 12, connected to adjustable spacer 420 are a firstdisc spring 430 and a second disc spring 440, which also include a firststraight radial extension 426 and a second straight radial extension446, respectively Each radial extension extends substantiallyperpendicular from the central axis A—A. Thus, a force from taperedroller bearing outer race 500 may be applied radially interior to firstdisc spring 430 and second disc spring 440 via first straight radialextension 436 and second straight radial extension 446 by flat portion510 above a bearing face which is interior to a corner radius of thebearing. Moreover, in this situation it may be advantageous to engage amulti-convolute spacer, such as in disc spring system 300 (FIG. 7) withsuch tapered roller bearings due to the more predictable nature ofcompression thereof, as described above. Further, disc spring system 400or a similar disc spring system using a multi-convolute spacer may bestacked with other disc spring systems or components to achieve adesired deflection and/or adjustability.

In another embodiment, FIG. 8 depicts an adjustable disc spring system350 having an adjustable spacer 355 which receives a first disc spring360 and a second disc spring 365 at outer radial ends thereof Thus, thedisc springs are positioned concentrically within the inner diameter ofthe adjustable spacer. Specifically, adjustable spacer 355 receivesfirst disc spring 360 at an offset 362 thereof and receives second discspring 365 at a second offset 367 thereof. As noted above for discspring system 250 (FIG. 4), first disc spring 360 includes an outerprojecting tip 363 and second disc spring 365 includes a second axiallyprojecting tip 369. These projecting tips may engage a shaft or othersurface interior to disc spring system 350. Adjustable spacer 355 has amulti-convolute form, similar to adjustable spacer 320. Thus, adjustablespacer 355 also has deflection and adjustability properties similar toadjustable spacer 355, as described above.

In another example, FIG. 13 depicts a first disc spring system 600 and asecond disc spring system 605, similar to disc spring system 10 depictedin FIG. 1, connected by a connecting member 610. Connecting member 610may be a simple roll formed “C” sectionally shaped ring connector forexample, as will be understood by those skilled in the art. Theconnection of a bottom disc spring 602 of first disc spring system 600and a top disc spring 612 of second disc spring system 605 inhibitsbottom disc spring 602 and top disc spring 612 from separating from oneanother. A more resilient contact is provided between disc spring system600 and disc spring system 605 with an inner surface (not shown) of acylinder, for example. Thus, first disc spring system 600 and seconddisc spring system 605 are maintained axially aligned during compressionof a first adjustable spacer 604 and a second adjustable spacer 614.Further, the use of one or more connecting members similar to connectingmember 610 facilitates stacking of multiple disc spring systems, such asfirst disc spring system 600 and second disc spring system 605. As notedabove, the stacking of multiple disc spring systems allows one to moreprecisely select the amount of deflection and adjustability desired in aparticular arrangement of disc springs and other components. Further,the connection of disc springs to each other, such as with connectingmember 610, allows a plurality of disc springs to act as a unit andreduces a risk of disc springs slipping past one another or otherwisefailing.

FIG. 14 illustrates a first disc spring system 700 connected to a seconddisc spring system 750 by a connecting washer 800. Connecting washer 800includes axially projecting thin cylinder ends 820 which are roll-formedover outer edges of a bottom disc spring 710 of first disc spring system700 and a top disc spring 760 of second disc spring system 750, forexample. Connecting washer 800 thus inhibits movement of a distal end712 of bottom disc spring 710 and a distal end 762 of top disc spring760 in an axial direction. Thus, over-stressing of bottom disc spring710 and top disc spring 760 is limited and alignment of the discs ismaintained, as will be understood by those skilled in the art. As notedabove for connecting member 610, the use of connecting washer 800facilitates stacking of disc spring systems thus allowing forselectability and variability in deflection and adjustability, asdesired. Further, additional deflection resistance may be provided byconnecting washer 800 itself

FIG. 15 depicts an example of a disc spring system 900 which includes afirst spring disc 910 and a second disc spring 920 received by anadjustable spacer 930. Also, first disc spring 910 includes a deflectionlimiting stop 912 and second disc spring 920 includes a deflectionlimiting stop 922. Deflection limiting stop 912 and deflection limitingstop 922 prevent over-stressing of first disc spring 910 and second discspring 920 by preventing movement of distal end 935 of adjustable spacer930 past the deflection limiting stops during compression of adjustablespacer 930.

In another example, as depicted in FIG. 16, a first disc spring system1000 is connected to a second disc spring system 1050 by an adjustablespacer 1100. First disc spring system 1000 includes a first adjustablespacer 1010 and second disc spring 1050 includes a second adjustablespacer 1060 which are aligned substantially parallel to adjustablespacer 1100, that is, they are aligned to be compressed in an axialdirection. Specifically, a compressible portion 1011 of first springsystem 1000, a second compressible portion 1062 of second disc springsystem 1050, and a third compressible portion 1110 of adjustable spacer1100 are adapted to be compressed in the axial direction. For example,by utilizing three adjustable spacers in this manner, disc spring system1000 and disc spring system 1050 may be held substantially parallel toone another as adjustable spacer 1010, adjustable spacer 1060, andadjustable spacer 1100 are compressed to adjust the disc springsrelative to one another.

Another embodiment of the present invention includes a first disc springsystem 1200 and a second disc spring system 1250, as depicted in FIG.17. A bottom disc spring 1210 of disc spring system 1200 includes anaxially projecting tip 1212 which forms a lip 1214 substantiallyparallel to an axial direction. Second disc spring system 1250 includesa top disc spring 1260 which may be received on lip 1214. Thus, firstdisc spring system 1200 may be stacked with second disc spring system1250 to provide flexibility in an amount of deflection when used in arestricted space, for example, a cylinder (not shown), and to preventrelative radial slippage between systems. When top disc spring 1260 isreceived by lip 1214, top disc spring 1260 may be inhibited from movingin an axial direction toward first disc spring system 1200 while bottomdisc spring 1210 may be inhibited from moving in an axial directiontoward disc spring system 1250. Thus, any failure caused by first discspring system 1200 or second disc spring system 1250 slipping relativeto one another may be inhibited or prevented.

Numerous alternative embodiments of the present invention exist. Forinstance, the disc springs described above may be utilized as sealingelements for various axial seal requirements. Frequently, such seals forstatic (i.e. non-rotating) or dynamic (i.e. rotating) applicationsrequire that seal elements thereof have significant flexibility whichmay be provided by the disc springs and adjustable spacers describedabove. For example, the disc springs may be pre-coated with a sealantbefore assembly or they may be coated after assembly of the disc springsystems. Such coatings may be a soft compliant material, such as butylrubber. Also, the coatings could be Teflon or a soft metal such as goldor silver. In a further example, ends of the disc springs describedabove may be relatively sharp and hard at their outer diameters suchthat a seal might be formed by imbedding the disc spring ends intoflanges being sealed (not shown), for example.

Further, the disc springs and adjustable spacers described above couldbe formed in any shape or size to allow resiliency, adjustability, andcompression in any desired direction, when received in any number ofrestricted spaces, as will be understood by those skilled in the art.Also, the adjustable spacers described above may be adapted to receiveonly one disc spring while ends of the adjustable spacer opposite thedisc spring may be adapted to engage different surfaces or objects, aswill be understood by those skilled in the art.

Although preferred embodiments have been depicted and described indetail herein, it will be apparent to those skilled in the relevant artthat various modifications, additions, substitutions and the like can bemade without departing from the spirit of the invention and these aretherefore considered to be within the scope of the invention as definedin the following claims.

1. A method of adjusting a disc spring system comprising: axiallyaligning at least one beveled disc spring with an adjustable spacer; andcompressing the adjustable spacer in a substantially axial directionrelative to said at least one beveled disc spring to plastically deformthe spacer.
 2. The method of claim 1 further comprising inserting the atleast one beveled disc spring into at least one entrapping flange of theadjustable spacer.
 3. The method of claim 1 wherein the compressing theadjustable spacer comprises placing an axial force on the at least onebeveled disc spring.
 4. The method of claim 1 wherein the at least onebeveled disc spring comprises at least one Belleville washer.